The patch titled mm: compaction: perform a faster migration scan when migrating asynchronously has been added to the -mm tree. Its filename is mm-compaction-perform-a-faster-migration-scan-when-migrating-asynchronously.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** See http://userweb.kernel.org/~akpm/stuff/added-to-mm.txt to find out what to do about this The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/ ------------------------------------------------------ Subject: mm: compaction: perform a faster migration scan when migrating asynchronously From: Mel Gorman <mel@xxxxxxxxx> try_to_compact_pages() is initially called to only migrate pages asychronously and kswapd always compacts asynchronously. Both are being optimistic so it is important to complete the work as quickly as possible to minimise stalls. This patch alters the scanner when asynchronous to only consider MIGRATE_MOVABLE pageblocks as migration candidates. This reduces stalls when allocating huge pages while not impairing allocation success rates as a full scan will be performed if necessary after direct reclaim. Signed-off-by: Mel Gorman <mel@xxxxxxxxx> Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx> Cc: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx> Cc: Rik van Riel <riel@xxxxxxxxxx> Cc: Johannes Weiner <hannes@xxxxxxxxxxx> Cc: Andy Whitcroft <apw@xxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/compaction.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff -puN mm/compaction.c~mm-compaction-perform-a-faster-migration-scan-when-migrating-asynchronously mm/compaction.c --- a/mm/compaction.c~mm-compaction-perform-a-faster-migration-scan-when-migrating-asynchronously +++ a/mm/compaction.c @@ -240,6 +240,7 @@ static unsigned long isolate_migratepage struct compact_control *cc) { unsigned long low_pfn, end_pfn; + unsigned long last_pageblock_nr = 0, pageblock_nr; unsigned long nr_scanned = 0, nr_isolated = 0; struct list_head *migratelist = &cc->migratepages; @@ -280,6 +281,20 @@ static unsigned long isolate_migratepage if (PageBuddy(page)) continue; + /* + * For async migration, also only scan in MOVABLE blocks. Async + * migration is optimistic to see if the minimum amount of work + * satisfies the allocation + */ + pageblock_nr = low_pfn >> pageblock_order; + if (!cc->sync && last_pageblock_nr != pageblock_nr && + get_pageblock_migratetype(page) != MIGRATE_MOVABLE) { + low_pfn += pageblock_nr_pages; + low_pfn = ALIGN(low_pfn, pageblock_nr_pages) - 1; + last_pageblock_nr = pageblock_nr; + continue; + } + /* Try isolate the page */ if (__isolate_lru_page(page, ISOLATE_BOTH, 0) != 0) continue; _ Patches currently in -mm which might be from mel@xxxxxxxxx are linux-next.patch mm-remove-call-to-find_vma-in-pagewalk-for-non-hugetlbfs.patch mm-page-allocator-adjust-the-per-cpu-counter-threshold-when-memory-is-low.patch mm-vmstat-use-a-single-setter-function-and-callback-for-adjusting-percpu-thresholds.patch mm-vmstat-use-a-single-setter-function-and-callback-for-adjusting-percpu-thresholds-fix.patch mm-vmstat-use-a-single-setter-function-and-callback-for-adjusting-percpu-thresholds-update.patch mm-vmstat-use-a-single-setter-function-and-callback-for-adjusting-percpu-thresholds-fix-set_pgdat_percpu_threshold-dont-use-for_each_online_cpu.patch writeback-io-less-balance_dirty_pages.patch writeback-consolidate-variable-names-in-balance_dirty_pages.patch writeback-per-task-rate-limit-on-balance_dirty_pages.patch writeback-per-task-rate-limit-on-balance_dirty_pages-fix.patch writeback-prevent-duplicate-balance_dirty_pages_ratelimited-calls.patch writeback-account-per-bdi-accumulated-written-pages.patch writeback-bdi-write-bandwidth-estimation.patch writeback-bdi-write-bandwidth-estimation-fix.patch writeback-show-bdi-write-bandwidth-in-debugfs.patch writeback-quit-throttling-when-bdi-dirty-pages-dropped-low.patch writeback-reduce-per-bdi-dirty-threshold-ramp-up-time.patch writeback-make-reasonable-gap-between-the-dirty-background-thresholds.patch writeback-scale-down-max-throttle-bandwidth-on-concurrent-dirtiers.patch writeback-add-trace-event-for-balance_dirty_pages.patch writeback-make-nr_to_write-a-per-file-limit.patch writeback-make-nr_to_write-a-per-file-limit-fix.patch vmscan-factor-out-kswapd-sleeping-logic-from-kswapd.patch mm-compaction-add-trace-events-for-memory-compaction-activity.patch mm-vmscan-convert-lumpy_mode-into-a-bitmask.patch mm-vmscan-reclaim-order-0-and-use-compaction-instead-of-lumpy-reclaim.patch mm-migration-allow-migration-to-operate-asynchronously-and-avoid-synchronous-compaction-in-the-faster-path.patch mm-migration-cleanup-migrate_pages-api-by-matching-types-for-offlining-and-sync.patch mm-compaction-perform-a-faster-migration-scan-when-migrating-asynchronously.patch mm-vmscan-rename-lumpy_mode-to-reclaim_mode.patch add-debugging-aid-for-memory-initialisation-problems.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html